Plymouth, MA Flood Zones: FEMA Basics
Plymouth is, by a wide margin, the largest town by land area in this site's South Shore cluster: 134.0 square miles total, of which 96.4 square miles is land and 37.5 square miles is water -- vastly larger than neighboring Duxbury's roughly 24 square miles of land or Hull's 2.8 square miles. That size is the single most important fact for understanding flood risk here, because it means "Plymouth" is not one coastal exposure profile. The town runs from the historic harbor and downtown waterfront, south along the coast through the village of Manomet and the eroding bluffs of Cedarville, out to the barrier sands of Plymouth Long Beach, and inland across miles of lakes, ponds, and cranberry-bog country that sit nowhere near tidal water. A property a few blocks from Plymouth Harbor and a property near Great Herring Pond or in the town's interior can have flood-zone realities that have almost nothing in common. This page explains how FEMA flood zones work in general, what is and is not confirmed about Plymouth's own flood-hazard picture, and where to get a determination for a specific address rather than guessing from geography alone.
FEMA Flood Zones, in Plain Terms
A FEMA flood zone is a designation shown on a community's Flood Insurance Rate Map (FIRM), used for insurance underwriting and building-code purposes -- not a description of how a place felt in the last storm anyone remembers. Zone X covers minimal-hazard areas outside the mapped 1%-annual-chance floodplain, with no federal mandatory flood-insurance requirement, though a lender can still require it; a related designation, X500, marks the more moderate 0.2%-annual-chance ("500-year") flood area. Zone AE is the mapped 1%-annual-chance, or "100-year," floodplain, tied to a specific Base Flood Elevation, and the related A1-A30 and AO designations cover similar 1%-annual-chance areas with slightly different mapping methods (numbered elevation zones and shallow-flooding/sheet-flow areas, respectively). Zone VE is the coastal high-hazard "wave action" zone, reserved for shoreline directly exposed to storm-driven waves, carrying the strictest construction rules -- elevated construction on pilings, no habitable space below the base flood elevation.
These zone lines are not permanent. FEMA periodically remaps communities as shoreline conditions, elevation surveys, and storm modeling change, so a parcel mapped one way on an older FIRM is not guaranteed to hold that designation on the current effective map. Nothing on this page assigns a zone to any specific Plymouth street, neighborhood, or address -- for that, use FEMA's own current map, covered at the end.
One Town, Several Very Different Flood Pictures
Plymouth's 96.4 square miles of land encompass the entire western shore of Cape Cod Bay, and the coastal exposure varies enormously along that shoreline alone. The harbor-front core around Plymouth Center sits behind Plymouth Beach and its barrier extension, Plymouth Long Beach, which itself has a well-documented history of storm-driven washover and repeated state-funded sand nourishment (a 2015 repair project, a 2018 nor'easter that tested it, and a separate, larger 2023 nourishment effort). Further south, the village of Manomet and the Cedarville area sit along active coastal bluffs and banks where the town's own conservation staff have described erosion severe enough, in places, that a property might not survive a 30-year mortgage cycle. White Horse Beach, also in Manomet, is a smaller dune-backed public beach with its own conservation setbacks. None of that is the same exposure as North, West, or South Plymouth's inland residential areas, or the town's extensive lake-and-pond interior around Great Herring Pond and the surrounding cranberry country, much of which sits miles from any tidal water and faces a fundamentally different set of flood considerations, if any.
The practical takeaway: a general statement like "Plymouth is a flood risk" or "Plymouth is not a flood risk" is not meaningful on its own for a town this size and this varied. What matters is where a specific parcel sits relative to the coast, a river, a pond, or low-lying ground -- which is exactly what a FEMA flood-zone lookup is built to answer on a parcel-by-parcel basis.
What This Research Could -- and Could Not -- Confirm
The research behind this page did not turn up a published, town-specific breakdown of which FEMA flood-zone designations (X, X500, AE, A1-A30, AO, VE, or otherwise) apply where within Plymouth, and it did not confirm Plymouth's participation in or class rating under FEMA's Community Rating System (CRS) -- the program that can reduce flood-insurance premiums for communities that exceed the National Flood Insurance Program's minimum floodplain-management standards. Because that could not be confirmed one way or the other, this page does not assert a CRS class for Plymouth, and it should not be assumed that Plymouth shares any neighboring cluster town's previously confirmed class, such as Marshfield's Class 7 rating. Anyone who needs Plymouth's current CRS status for an insurance decision should confirm it directly against FEMA's own current CRS community list rather than relying on this page or any other general summary.
What is well documented, separate from any specific zone designation, is that Plymouth's coastal edge is an active and ongoing subject of erosion monitoring and storm-protection spending: documented bluff and bank erosion along Manomet Avenue, Manomet Point Road, and Nameloc Drive in Cedarville, including at least two homes relocated away from eroding coastal banks; and a multi-year, multi-million-dollar history of state-funded sand nourishment on Plymouth Long Beach to repair storm-washover damage and reduce the risk of a full breach into Plymouth Harbor. That activity is a strong signal that this stretch of coastline carries real, current flood and erosion exposure -- but it is not a substitute for, and should not be read as, a FEMA zone determination for any individual property.
How to Actually Check a Plymouth Parcel
Given how much this town varies from the harbor to Manomet to Cedarville to its inland pond country, a parcel-specific FEMA determination matters more in Plymouth than in almost any smaller, more geographically uniform town in this cluster. For that, go directly to FEMA's Map Service Center (msc.fema.gov), enter the property address, and pull the current effective Flood Insurance Rate Map panel. That lookup will show whether a given parcel falls in Zone X, X500, AE, A1-A30, AO, VE, or another designation, along with the Base Flood Elevation where one applies.
From there, confirm any building, elevation, or floodplain-management requirements directly with the Town of Plymouth itself, since parcel-specific detail -- and Plymouth's actual current CRS participation and class, if any -- sits with the town and with FEMA's own records rather than with any general research summary. If you are evaluating a property anywhere along the harbor, in Manomet or Cedarville, near Plymouth Long Beach or White Horse Beach, or along one of the town's inland ponds, a flood-zone determination from a title company or flood-certification service, ordered as part of a mortgage closing, and a conversation with a local, Plymouth-familiar insurance agent and a licensed engineer or surveyor about zone-specific premium and construction requirements are both worth doing before you are under contract, not after.
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Get a Free Agent Referral →Independent research. No ads. No sponsored listings. General FEMA flood-zone category descriptions (Zone X, X500, AE, A1-A30, AO, VE) and the Community Rating System reflect publicly documented National Flood Insurance Program definitions and are not specific to any Plymouth parcel. Plymouth's geography (134.0 square miles total, 96.4 square miles land, 37.5 square miles water, encompassing the western shore of Cape Cod Bay plus the villages of Manomet and Cedarville, the Plymouth Long Beach barrier beach, and an extensive inland lake/pond and cranberry-bog interior) reflects Wikipedia-sourced infobox data. Manomet and Cedarville erosion detail (documented erosion along Manomet Avenue, Manomet Point Road, and Nameloc Drive, and at least two homes relocated away from eroding coastal banks) and Plymouth Long Beach nourishment history (a state-funded FY2015 washover-repair project, a March 2018 nor'easter credited with testing it, and a separate, larger 2023 nourishment project) are drawn from Plymouth Independent reporting, the Town of Plymouth, Mass.gov project records, and the Community Land & Water Coalition, an advocacy source whose characterization of the 2023 project is treated as opinionated rather than independently adjudicated. This research did not confirm a specific FEMA Community Rating System (CRS) class for Plymouth, or a published breakdown of which flood-zone designations apply to which parts of town, and neither is asserted here -- do not assume Plymouth shares any other cluster town's previously confirmed CRS class, such as Marshfield's Class 7 rating. This page is general education, not a flood-zone determination -- for an address-specific FEMA flood zone, use FEMA's Map Service Center (msc.fema.gov) directly, contact the Town of Plymouth directly for parcel-specific information, and confirm floodplain-management and construction requirements with a licensed engineer, surveyor, or insurance professional before making any purchase or building decision.